1. Field of the Invention
The invention relates to connector terminals and, more particularly, to a terminal for at least one electrical conductor, where the terminal comprises a terminal base and a clamping spring applying a clamping force applied by to clamp the electrical conductor to the terminal base.
2. Description of the Related Art
Terminals are used in a multiplicity of different electrical devices and systems, as well as generally for electrical installation purposes. With such terminals, in contrast to a screw-type terminal, a clamping force is applied by a clamping spring. The clamping of an electrical conductor is accomplished, for example, in that a clamping edge clamps a bared end of the electrical conductor against the terminal base, as shown in a known terminal depicted in FIG. 1. Hope, the clamping edge is disposed on the clamping spring itself. Normally, the clamping action is effected such that the inserted end of the electrical conductor causes the clamping edge bearing on the terminal base to move back. The spring can also be tensioned by an auxiliary tool, e.g., a screwdriver. For that purpose, an opening is provided in a housing of the terminal through which the auxiliary tool is introduced, and in the process acts on the clamping spring. In this way, it is also possible to release a clamped electrical conductor once more.
A disadvantage with these generic terminals is a lower level of clamping reliability than in the case of screw-type terminals, i.e., with terminal contacts which are exposed to vibrations or other mechanical influences. The clamping force exerted by the clamping spring is often not enough to permanently clamp an electrical conductor permanently with a low contact resistance against the terminal base.
A high level of clamping reliability to avoid system outages is required, particularly in the field of automation technology comprising extensive electrical installations such as the wiring of power supplies in switching cabinets, for example. In particular, the automobile industry stipulates that only screw-type terminals should be used in switching cabinets for car production plants.
This requirement is also fulfilled by a combination terminal in DE 35 04 317 A1. With this solution, a clamping device with, a clamping spring, and a clamping device with a clamping screw are provided in a housing. An electrical conductor is initially clamped to a terminal base by a clamping spring. In addition to the clamping spring, the electrical conductor can also be clamped against the terminal base by a clamping screw. A disadvantageous aspect therein is the amount of space that must be provided for the two clamping devices.